title: Expression of pituitary adenylate cyclase-activating peptide (PACAP) and PAC1 in the periodontal ligament after tooth luxation.
abstract: Pituitary adenylate cyclase-activating peptide (PACAP) is widely distributed throughout the nervous system. PACAP not only acts as a neurotransmitter but also elicits a broad spectrum of biological action via the PACAP-specific receptor, PAC1. However, no studies have investigated PACAP and PAC1 in the periodontal ligament (PDL), so we aimed to perform this investigation in rats after tooth luxation. In the PDL of an intact first molar, there are few osteoclasts and osteoblasts. However, at days 3 and 5 after luxation, large PAC1-positive cells, thought to be osteoclasts because of their expression of the osteoclast marker, tartrate-resistant acid phosphatase, were detected in appreciable numbers. Osteoblast numbers increased dramatically on day 7 after luxation, and PAC1-positive mononuclear small cells were increased at day 14, many of which expressed the osteoblast marker, alkaline phosphatase. PACAP-positive nerve fibers were rarely detected in the PDL of intact first molars, but were increasingly evident at this site on days 5 and 7 after luxation. Double-immunofluorescence analysis demonstrated the relationship between PACAP-positive nerve fibers and PAC1-positive osteoclasts/-blasts in the PDL. At 5 days after luxation, PACAP-positive nerve fibers appeared in close proximity to PAC1-positive osteoclasts. At 7 days after luxation, PACAP-positive nerve fibers appeared in close proximity to PAC1-positive osteoblasts. These results suggest that PACAP may have effects on osteoclasts and osteoblasts in the PDL after tooth luxation and thus regulate bone remodeling after these types of injury.
authors.affiliation: Division of Orthodontics and Dentofacial Orthopedics, Department of Translational Medicine, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan.
authors.forename: Sayako
authors.initials: S
authors.lastname: Nonaka
authors.forename: Hideki
authors.initials: H
authors.lastname: Kitaura
authors.forename: Keisuke
authors.initials: K
authors.lastname: Kimura
authors.forename: Masahiko
authors.initials: M
authors.lastname: Ishida
authors.forename: Teruko
authors.initials: T
authors.lastname: Takano-Yamamoto
mesh_terms: D000818:Animals; D002452:Cell Count; D005455:Fluorescent Antibody Technique; D008297:Male; D009412:Nerve Fibers / Q000378:metabolism; D010006:Osteoblasts / Q000378:metabolism / Q000473:pathology; D010010:Osteoclasts / Q000378:metabolism / Q000473:pathology; D010513:Periodontal Ligament / Q000294:innervation / Q000378:metabolism*; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide / Q000378:metabolism*; D014084:Tooth Avulsion / Q000378:metabolism* / Q000473:pathology
chemical_list: D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide